MAPT and early-onset autosomal dominant Alzheimer disease: All of the six tau isoforms are hyperphosphorylated and aggregated into neurofibrillary tangles (NFTs) in Alzheimer’s disease (AD) brain (Grundke-Iqbal et al., 1986; Iqbal et al., 1986, 1989; Lee et al., 1991; Goedert et al., 1992).